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HOx observations over West Africa during AMMA: impact of isoprene and NOx
Aircraft OH and HO2 measurements made over West Africa during the AMMA field campaign in summer 2006 have been investigated using a box model constrained to observations of long-lived species and physical parameters. "Good" agreement was found for HO2 (modelled to observed gradient of 1.23 ± 0.11). However, the model significantly overpredicts OH concentrations. The reasons for this are not clear, but may reflect instrumental instabilities affecting the OH measurements. Within the model, HOx concentrations in West Africa are controlled by relatively simple photochemistry, with production dominated by ozone photolysis and reaction of O(1D) with water vapour, and loss processes dominated by HO2 + HO2 and HO2 + RO2. Isoprene chemistry was found to influence forested regions. In contrast to several recent field studies in very low NOx and high isoprene environments, we do not observe any dependence of model success for HO2 on isoprene and attribute this to efficient recycling of HOx through RO2 + NO reactions under the moderate NOx concentrations (5–300 ppt NO in the boundary layer, median 76 ppt) encountered during AMMA. This suggests that some of the problems with understanding the impact of isoprene on atmospheric composition may be limited to the extreme low range of NOx concentrations
Environmental monitoring : phase 5 final report (April 2019 - March 2020)
This report presents the results and interpretation for Phase 5 of an integrated environmental
monitoring programme that is being undertaken around two proposed shale gas sites in England –
Preston New Road, Lancashire and Kirby Misperton, North Yorkshire. The report should be read
in conjunction with previous reports freely available through the project website1
. These provide
additional background to the project, presentation of earlier results and the rationale for
establishment of the different elements of the monitoring programme
Environmental monitoring : phase 4 final report (April 2018 - March 2019)
This report describes the results of activities carried out as part of the Environmental
Monitoring Project (EMP) led by the British Geological Survey (BGS) in areas around two
shale gas sites in England – Kirby Misperton (Vale of Pickering, North Yorkshire) and Preston
New Road (Fylde, Lancashire). It focuses on the monitoring undertaken during the period April
2018–March 2019 but also considers this in the context of earlier monitoring results that have
been covered in reports for earlier phases of the project (Phases I–IV)
2
.
The EMP project is a multi-partner project involving BGS together with Public Health England
(PHE), University of Birmingham, University of Bristol, University of Manchester, Royal
Holloway University of London (RHUL) and University of York. The work has been enabled
by funding from a combination of the BGS National Capability programme, a grant awarded
by the UK Government’s Department for Business Energy & Industrial Strategy (BEIS) and
additional benefit-in-kind contributions from all partners.
The project comprises the comprehensive monitoring of different environment compartments
and properties at and around the two shale-gas sites. The component parts of the EMP are all
of significance when considering environmental and human health risks associated with shale
gas development. Included are seismicity, ground motion, water (groundwater and surface
water), soil gas, greenhouse gases, air quality, and radon.
The monitoring started before hydraulic fracturing had taken place at the two locations, and so
the results obtained before the initiation of operations at the shale-gas sites represent baseline
conditions. It is important to characterise adequately the baseline conditions so that any future
changes caused by shale gas operations, including hydraulic fracturing, can be identified. This
is also the case for any other new activities that may impact those compartments of the
environment being monitored as part of the project.
In the period October 2018–December 2018, an initial phase of hydraulic fracturing took place
at the Preston New Road (PNR) shale-gas site (shale gas well PNR1-z) in Lancashire. This was
followed by a period of flow testing of the well to assess its performance (to end of January
2019). The project team continued monitoring during these various activities and several
environmental effects were observed. These are summarised below and described in more
detail within the report. The initiation of operations at the shale-gas site signified the end of
baseline monitoring. At the Kirby Misperton site (KMA), approval has not yet been granted
for hydraulic fracturing of the shale gas well (KM8), and so no associated operations have
taken place during the period covered by this report. The effects on air quality arising from the
mobilisation of equipment in anticipation of hydraulic fracturing operations starting was
reported in the Phase III report, and in a recently published paper3
. Following demobilisation of the equipment and its removal from the site, conditions returned to baseline and the on-going
monitoring (reported in this report) is effectively a continuation of baseline monitoring
State of nature 2023
This is the fourth State of Nature Report. It provides a comprehensive overview of species trends across the UK, including specific assessments for England, Northern Ireland, Scotland and Wales, and for the UK’s Overseas Territories
The geology of part of the Carr Boyd Rocks Complex and its associated nickel mineralization, Western Australia
Ultramafic-mafic intrusive complex, Archean, chemical and mineralogical data, stratigraphy, petrography, three compositionally different but related magmas, crystallization sequences, cut by breccia pipes of bronzite pegmatoid (in third), nickel in pipes
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